Chapter 6pg. 116-124

PHOTOSYNTHESIS

The Light Reactions•S

teps:•L

ight absorption Electron Transport Chain Chemiosmosis

Light Reaction•L

ocation: Thylakoid Membrane•R

eactants: Light and H2O•P

roduct: O2 (waste product) and ATP

Calvin Cycle

•Location: Stroma

•Reactants: CO2 and ATP

•Product: C6H12O6

(sugar)

Light and Pigments

• Light• Visible light includes the

colors of the rainbow• Pigments• Compounds that absorb

specific colors of light. Absorbed colors are not visible.

Visible Light Spectrum

•The color you see is what the object DOES NOT absorb (reflected)

1. Chlorophyll a – Pigment that absorbs light energy

• Absorbs reds and blues• Located in thylakoid membrane.

Chloroplast are green because they don’t absorb green!

2. Carotenoids •Three pigments (Orange, Brown, and Yellow) that focus on absorbing blues and greens

These colors are seen in the fall and in vegetables

Calvin Cycle

•Location: Stroma

•Reactants: CO2 and ATP

•Product: C6H12O6

(sugar)

LIGHT REACTIONS:Make energy in the form of ATP and e- carrier

CALVIN CYCLE:Uses the ATP and e- carrier to make carbohydrates

1. Light absorption (by plant pigments)2. Electron transport chain (making e- carrier) 3. Chemiosmosis (making ATP)

4. Calvin Cycle (making carbohydrates from CO2)

PHOTOSYNTHESIS OCCURS IN TWO PARTS SUMMARY

Rate of photosynthesisPhotosynthesis is affected by the environment:• Light and Temperature

•The rate of photosynthesis increases as light intensity increases.•Limited to a maximum rate once all available electrons are excited.

•The rate of photosynthesis increases as temperature increases, over a certain range.•Rate peaks when the enzymes begin to become ineffective with increased temperature.